Electromagnetic coils



0a. 20, 1970 R. E. BELL 3,535,666

ELECTROMAGNETIC. C OILS Filed Dec. 5, '1968 INVENTOR.

RICHARD E. LL

AGENT United States Patent 3,535,666 ELECTRGMAGNETIC COlLS Richard E. Bell, Princeton, Ind., assignor to American Machine & Foundry Co., a corporation of New Jersey Filed Dec. 5, 1968, Ser. No. 781,456 Int. Cl. H01f 15/10 US. Cl. 336-192 8 Claims ABSTRACT OF THE DISCLOSURE Wire wound coil terminal means providing a pair of connectors held against movement on the coil. Each connector includes a pad portion positioned on the winding and a leg portion so that an end of the winding is connected to one portion and a lead is connected to the other. A bridge which joins the connectors together until the terminal means is retained on the coil, is spaced from the winding and is thereafter removed to electrically isolate the connectors.

This invention relates generally to electromagnetic coils having wire windings and more particularly to means for connecting wire leads to the ends of the wound wire.

Connector means for coils can be divided generally into two types. The first are terminal connectors which are mounted on the spool and normally provide electrical connections only at the end of the coil. The second are lead connections insulated from and retained in place on the wire windings by the coil wrapping to provide electrical connections either at the ends of the coil or at any desired locations along its length.

The present invention is primarily concerned with the latter. It has been found that connections between an end of the wound wire and normally an insulated wire lead cannot be held completely immovable and the wound wire adjacent the connection tends to break due to its fragile nature. These connections can be held against movement to a greater degree by use of a small connecting pad of a conductive material. However, such small pads are difiicult to handle when effecting a connection.

Therefore, an object of the present invention is to provide terminal means of the type to be retained in place on the wire winding of a coil for connecting with facility leads to the free ends of the winding and the resulting connections being capable of being held immovable by the coil wrapping.

Another object of the present invention is to provide the foregoing terminal means which is a single member to which the freewire ends and the leads are connected, and which has a deformation with a removable portion thereof for electrically isolating the electrical connections after the terminal means has been mounted.

And another object of the present invention is to provide the foregoing terminal means having a U-shaped deformation between its end portions providing a pair of leg portions each forming a connector with a different end portion of the terminal means, and a removable bight portion releasably joining the connectors together.

The present invention contemplates terminal means for being retained in place on a wire winding of a coil and for connecting a pair of leads to the free end of the winding on which is mounted comprising a pair of spaced connectors made of electrically conductive material each having a pad portion and a leg portion, one of said por- M "ice for connecting said pair of connectors together until said terminal means is mounted and being removable therefrom for electrically isolating each of said connectors from the other.

The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein several embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.

FIG. 1 is a plan view and FIGS. 2 and 3 are elevational views of a coil in three stages of being completed in acordance with the present invention,

FIG. 4 is a perspective view of the novel connector embodied in the coil of FIGS. 1 to 3, and

FIGS. 5 and 6 are perspective views of other forms of connectors.

Referring now to the drawings and particularly to FIGS. 1 to 4, an electromagnetic coil C is provided with a bobbin 10 of a dielectric material which has a wire winding 11 and the usual magnetic core (not shown). The core may be provided prior to or after winding, as desired. A very fine gage wire is used for the winding 11 and a small piece of tape (not shown) may be applied to hold the last turns against unwinding. Because of the fragile nature of the wire used for the winding 11, it is preferable to provide stronger terminal connections or Wire leads prior to completion of the coil C. For this purpose, the ends 12 of the wire winding 11 remain free, as shown in FIG. 1.

While wire coils are provided with many types of terminal connections, the present invention is particular- 1y concerned with terminal connections for isulated wire leads where the termial connections are not mounted or mechanically retained by the coil spool. It has been common practice to solder the ends of the wound wire directly to insulated wire leads, and to bind the soldered connections and the adjacent portions of the leads by the coil with the coil insulating wrap. It has been found that this type of connection is relatively difficult to make and that the formed connection often is not held completely immovable which, in many instances, eventually causes the end of the wound wire adjacent the connection to break. Alternatively, small pads of conductive material have been used to eliminate the foregoing conditions but, because of their size, are hard to handle and difficult to hold in a fixed position which causes problems when connecting the wire leads and/or the ends of the wound wire.

Therefore, in accordance with the present invention, an elongated flat Wire strip 15, as shown in FIG. 4, is provided with a pair of end portions 18 disposed on a common plane, and a U-shaped deformation disposed on one side of the common plane and having a bight portion 16 connecting two leg portions 17 thereof together. This deformation acts as a bridge to connect the end or pad portions 18 of the connector 15 to each other.

A pair of insulated wire leads 13 may be provided each being conductively joined, by solder or any other suitable means, to a different end or pad portion 18 as shown in FIG. 1. The connector 15 is then positioned axially on the coil C with a suitable film insulation (not shown) between the winding 11 and the end or pad portions 18.

When the connector 15 is positioned, it is tied or bound in place on the coil C by Wrappings of a thin filament 14 of cotton, nylon or any other suitable material, as shown in FIG. 2. The bight or bridge portion 16 is then removed and the free ends 12 of the wire winding 11 are each wrapped on a different leg portion 17 of the connector 15,

and retained by a spot of solder or any other suitable material. It should be readily seen that both terminal con nections have been made with an intermediate pad member provided by adjacent portions 17 and 18- between each wire end 12 and the corresponding wire lead 13 without the necessity of handling excessively small parts. It also should be realized that when joining the free ends 12 of the fragile wound wire 11 to the legs 17, the connector 15 is secured to the coil C. This greatly facilitates making the connections and thereby substantially reduces the probability of breakage of the wire ends 12.

Depending upon the desired locations, the insulated wire leads 1.3 can remain, as shown in FIG. 2, extending axially from the connector 15 or may be bent to extend radially from the coil C and substantially parallel to the leg portions 17. To complete the coil C, a tape 19 of dielectric material is wrapped around the wire winding 11 from one end of the bobbin to the other, as shown in FIG. 3. The leg portions 17 may be trimmed or bent flat against the adjacent foot portions 18 before wrapping so they are covered by the tape 19 or may extend through the initial wrapping. The legs 17 Would then be trimmed or bent flat against the wrapping to be covered by another run of the tape 19.

Alternatively, the free ends 12 of the wire winding 11 can be wrapped each on a different end or pad portion 18 of the connector and be retained thereon by solder or any other suitable material. The connector 15 is then suitably positioned and bound in place on the coil C as was heretofore described. The wire leads '13 are each conductively connected to a different one of the leg portions 17 either before or after the connector 15 is bound in place on the coil C. The bridge or bight portion 16 is is then removed and the coil C is wrapped with tape 19 as was previously described. The legs 17 will be bent before or after wrapping depending upon whether or not the wire leads 13 are connected thereto.

It should be understood that a free end 12 of the wind ing 11 can be connected to either a leg portion 17 or the adjacent end portion 18, and the corresponding Wire lead 13 then is connected to the other portion.

When forming the connector 15, the width of the bight portion 16 can selectively be reduced to facilitate removal when separating or electrically isolating each of the pad portions 18 with the respective leg portions 17, wire ends 12 and Wire terminals 13 from each other. This width reduction is a matter of choice as is illustrated by the modified form of connector 20 as shown in FIG. 5.

The deformation of the modified connector 20 provides a relatively short bight portion 21 connecting the two leg portions 22 to each other. The pad portions 23, in this instance, are bent providing end or terminal portions 24 which extend obliquely therefrom. With the connector 20, the wire leads 13 and free wire ends 12 are connected alternatively to the leg portions 22 and end portions 24.

A third or still another modified form of connector 25, shown in FIG. 6, is provided with flat Wire leg portions 27, pad portions 28 and end or terminal portions 29 which correspond to similar portions of the connector 20. In this instance, however, the leg portions 27 are spaced edgewise along a common plane and the end or terminal portions 29 are substantially parallel to the leg portions 27. The wire leads 13 and the free ends 12 of the wound wire 11 are alternatively connected to the leg portions 27 and the end portions 29 of the connector 25. The bight portion 26 is a wireform or is a flat wire reduced along both edges, and is of a U-shape.

It should be understood that the connectors 15, 20 and are provided for illustrating various forms which may be used but it should be understood that there is no intent to limit the present invention thereby.

Although several embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may be made in the design and ar- 4 rangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. In a coil construction, the combination comprising:

a spool and a wire winding on said spool,

a terminal means providing a pair of connectors of electrically conductive material each with leg and pad portions, and a removable bridge connected at its ends to said leg portions thereby spacing said connectors from each other and being spaced from said pad portions by said leg portions,

said terminal means positioned on said coil with said bridge spaced from said Winding and said pads adjacent said winding;

means for retaining said terminal means in place on said coil and holding said connectors against movement,

one of said portions of each of said connectors being connected to a different end of said wire winding and a pair of lead means each connected to a different one of the other of said portions, and

said bridge being removable from said terminal means to thereby electrically isolate each of said connectors from the other.

2. The coil construction in accordance with claim 1,

wherein said leg portion of each connector is bent against said pad portion of said connector, and

a dielectric wrapping applied on said coil encloses said winding and connectors.

3. The coil construction in accordance with claim 1,

wherein said terminal means being an elongated strip of electrically conductive material,

the ends of said strip being disposed in substantially a common plane and providing said pad portions of said connectors,

said strip having a U-shaped deformation disposed between its ends and on one side of said common plane, and

said deformation having a pair of legs providing said leg portions of said connectors and a bight providing said bridge.

4. The coil construction in accordance with claim 3,

and

said bight being narrower in width than the legs of said deformation.

5. The coil construction in accordance with claim 3,

and

said pad portions being spaced endwise from each other and the spaced ends thereof each being connected to a different one of said leg portions, and

the other end of each of said pad portions opposite from said leg portion attached thereto extending away from said common plane and on the same side thereof as said deformation.

6. The coil construction in accordance with claim 1,

and

each of said connectors being of an elongated strip,

said pad portions being disposed in substantially a common plane,

said leg portions extending from said pad portions on the same side of the common plane and being disposed in another plane transverse to said common plane, and

said bridge joining said leg portions disposed on said other plane.

7. The coil construction in accordance with claim 6,

and

said bridge being a U-shaped wire spacing said connectors edgewise from one another.

8. The coil construction in accordance with claim 6,

and

each of said connectors having another leg portion ex- 6 tending from said pad portion and being disposed on 2,939,096 4/ 1960 Gordon 336-192 X the same side of the common plane as said leg por- 3,054,027 9/1962 Barrick 336192 X tions disposed on the other plane, and 3,117,297 1/ 1964 De Gier 3 l7261 X said other leg portions being spaced from the other 3,259,862 7/1966 Richard 336192 X plane each on opposite side thereof from the other. 5 3,356,911 12/1967 Galvagni 317'-258 X 3,459,875 8/1969 Fork 17449 References Cited UNITED STATES PATENTS 2,471,869 4/1949 Gebel. 10 US. Cl. X.R. 2,742,686 4/1956 Franz. 29-630 ELLIOT A. GOLDBERG, Primary Examiner 

